Pakistani police fired tear gas, detained opposition leaders and ransacked the offices of a major television station yesterday as protests escalated over the ousting of the country's top judge.

Riot police smashed into the offices of Geo television in Islamabad after editors refused to stop transmitting pictures of police clashing with stone-throwing protesters. Glass doors were broken and journalists were assaulted by officers who ordered them to remove a rooftop camera with a panoramic view of the street violence.

"Look, this is our government's freedom of press," said producer Qaisar Butt, standing amid glass shards in an office that smelled of tear gas.

President Pervez Musharraf later rang the television station to make an unprecedented live apology. "The first thing is that it was a very sad incident. It should have not happened, and I condemn it," he said, vowing to "take action" against the culprits.

The incident was a measure of how badly government efforts to deflate the judicial crisis are failing. For the past eight days Gen Musharraf has been trying to sack the chief justice, Iftikhar Muhammad Chaudhry, claiming he is guilty of unspecified charges of misconduct.

But the judge and his swelling brigade of supporters, who have paralysed the courts, say the charges have been cooked up to ensure Gen Musharraf can be easily re-elected as president later this year.

Yesterday hundreds of lawyers and opposition politicians pushed past police barricades and gathered outside the supreme court where a panel of senior judges started disciplinary hearings against Justice Chaudhry, who was greeted with roars of approval.

A government lawyer, who declined to be named, was among the protesters. "This country has very weak institutions, all we have are symbols. Now even the symbols are being destroyed," he said.

"The government have gone mad, crazy," said Senator Enver Baig of the Pakistan People's party. "When the chief justice is being treated like a criminal, what's happening to this country?"

The crisis is ballooning out of the government's control and clumsy efforts to curb the fallout have hurt Gen Musharraf's fragile democratic credentials. Scores of opposition activists have been rounded up in recent days. A source in Lahore said the police had been given a list of lawyers for arrest. Yesterday in Islamabad Qazi Hussain Ahmed, leader of the Jamaat Islami religious party, was arrested. In Lahore a former president of Pakistan, Rafiq Tarar, was bundled into a police vehicle and driven away.

On Thursday the government media regulator ordered Geo television to take a popular chatshow, which intended to discuss the controversy, off air. "This raises serious questions about how much freedom is allowed when the subject is too close to home," said Imran Aslam, president of Geo.

The controversy is taking Gen Musharraf, famous for his boastful self-confidence, into unknown territory.

Newspaper columnists have drawn parallels with another general turned leader, Julius Caesar, and the ides of March.

"Caesar has shown his face and it is not a pretty sight," wrote Moeen Cheema in the Daily Times.

On Thursday the president attended a party thrown by the foreign minister, Khurshid Kasuri, in Lahore. One socialite who was there described the atmosphere as "a bit like the last days of the Raj".

Gen Musharraf's difficulty is that Justice Chaudhry, despite enormous pressure, refuses to resign. At yesterday's sitting of the supreme judicial council his lawyers argued that the hearing was biased against him. The next hearing is scheduled for March 21.

Gen Musharraf has promised not to interfere in the process but analysts say it would be unthinkable for him to reinstate an official who has boldly defied him. "He is a general and he is president. He can do whatever he wants," said SM Shirazi, a protesting lawyer.

But the longer the crisis drags on, the more damage it does to Gen Musharraf's standing at a sensitive time and at the start of an election year.